In a medium-size bowl, whisk together the flour, baking soda, ginger, cinnamon, cloves and salt. Set aside.
In a large bowl, beat butter and sugar until smooth. Beat in egg, then molasses. Stir flour mixture into butter mixture. Divide dough into 2 halves. Wrap; chill 2 hours.
Heat oven to 350 degrees F. On a well-floured surface, roll half of dough to 1/8-inch thickness. Cut shapes with assorted-size gingerbread cookie cutters; transfer to ungreased baking sheets. Reroll scraps; cut. Repeat with rest of dough.
Bake at 350 degrees for 13 minutes. Transfer cookies to racks to cool. Decorate with Royal Icing (recipe follows) and assorted candies. Makes 2-1/2 dozen assorted-size cookies.
In a medium-size bowl, combine confectioners sugar, powdered egg whites and water. Beat on medium speed for 1 minute to blend, then increase speed to high and beat 5 minutes until thick and shiny. Transfer to a pastry bag fitted with a round tip, or a resealable plastic bag; snip small corner off bag. Pipe icing over cookies. Makes 1-1/2 cups icing.